Destroy or Keep Title?

[Sergeant Flutter]

I'm playing as Aragon, I got a Papal Invasion of Castile. I won.

I destroyed K_Castile and now D_Castile is drifting into Aragon. K_Castile will be titular soon.

Should I reform Castile? Or would it be beneficial to keep it destroyed?

 

[thevmag]

Unless it's somehow going to derail your future plans, I say let it drift in. Once it's titular, create the title of Castile for free monthly prestige without any vassal begging for it.

 

[Sunspawn]

Unless you are elective, in which case don't. Titular elective titles are no longer free designation, since every duke will have a vote due to no de-jure.

 

[Silversweeeper]

If you have primogeniture or seniority, creating the title has a number of advantages: More monthly prestige, many factions splitting by title ("Lower CA in Aragon/Castile" and "X for Aragon/Castile"), and a fallback title if something bad happens and you lose one title (due to an invasion, a crusade-type war, or just factions/adventurers), at the very least.